Setting the Bar for Agile Architecture

My five months with EnterpriseWeb have run their course, and I’m returning to the world of advisory, analysis, and architecture training with my new company, Intellyx, and this, the inaugural issue of our Cortex newsletter. After a dozen years with ZapThink, doing my best to help organizations around the globe get architecture right, you might wonder why I took a detour as Chief Evangelist for a vendor. The answer: EnterpriseWeb has brought technology to market that can upend the entire Agile Architecture discussion. They have set the bar for what it means to build a platform that can enable organizations to achieve the elusive business agility benefits that SOA promised but never delivered. And if a five-person company out of upstate New York can do that, then anybody can.

As of today I return full time to being a chief evangelist for the style of Enterprise Architecture I refer to as Agile Architecture in my book, The Agile Architecture Revolution. In that book I talk about REST-Based SOA, Cloud Computing, mobile technologies, and a host of other modern enterprise technology trends that are shaking up IT departments as they try to get a handle on the business value such technologies promise. And yet, I’ll be the first to admit that the book didn’t go far enough. You could take every word I wrote to heart and still not know how to architect agility in your organization. There were pieces missing from the story – and all these missing elements centered on the fundamental challenge of distributed computing.

The central challenge of distributed computing, of course, is how to get your various distributed bits to communicate with each other properly. Since those distributed components are typically heterogeneous, we must somehow come up with a common means of establishing interaction among components everybody can agree on. Yet, once we do that, we’ve necessarily compromised on flexibility, because changing how our components interact is a difficult, complex endeavor. Agile Architecture must solve this problem.

This problem pervades the entire history of APIs, from remote procedure calls to Web Services to RESTful APIs and everything in between. We must somehow contract interfaces in order to abstract the underlying functionality, thus providing loose coupling and with it, some measure of flexibility within the underlying code. Yet the very act of introducing such contracts (including REST’s uniform interface) is a compromise, since the interface itself now lacks flexibility. Basically, we look at the world of distributed computing and convince ourselves that the only way to get this stuff to work at all is to give up agility. The end result? Instead of being an enabler of business agility, enterprise IT is now cast in the role of limiter of business agility.

The central technical challenge for Agile Architecture, therefore, is how to achieve functionality and performance without having to trade off flexibility. This central compromise of distributed computing is the nut that EnterpriseWeb has been able to crack by adding an additional layer of abstraction over the entire distributed environment, coupled with an agent-oriented runtime engine that resolves abstracted references dynamically in real time. The bottom line: at least one vendor in the marketplace has shown that it is possible to deliver on the promise of Agile Architecture. And if one can, so can others.

The Four Central Patterns of Agile Architecture

Now it’s time for me to take off my EnterpriseWeb hat and put it in a drawer. In its place goes the Intellyx hat, blue brain and all. After all, the point of this article isn’t to talk about what a single vendor has accomplished. Rather, my goal is to lay out the essential patterns of Agile Architecture that heretofore have been difficult or impossible to implement in practice.

The context for these central patterns of Agile Architecture is the concept of architecting at the “meta” level I discuss in my book – the higher level of abstraction that EnterpriseWeb has been able to implement. At this meta level, there are four central patterns of Agile Architecture that are essential to resolving the fundamental compromise of distributed computing:

Dynamic Coupling. Tightly coupled interfaces require detailed knowledge of both sides of a distributed computing interaction, and any change on one side might break the other. Contracted interfaces introduce loose coupling, implementing an abstraction that separates interface from implementation, thus allowing changes to the implementation, but at the expense of a static interface. With dynamic coupling, interface differences are resolved dynamically at run time. The underlying integration engine must be able to find all relevant metadata and resolve any interaction issues in real time in order to allow the metadata to change from one request to the next.

Dynamic Schemas. Neither the WSDL files that specify Web Services, nor the URIs, HTTP verbs, and Internet Media Types that specify RESTful APIs adequately contract the message semantics for any interaction. As a result, metadata describing such semantics are scattered about in XML schemas or Custom Media Types or other arbitrary places, leading to the reintroduction of tight coupling and inflexibility. Dynamic schemas abstract all such semantic metadata in a consistent way, relying once again upon the integration engine to resolve these dynamic schemas for each interaction at run time.

Extreme Late Binding. Remember the original promise of SOA registries and the ungainly UDDI standard? The idea was that a Service consumer could automatically look up a Web Service at run time, and based upon the WSDL file it found as a result, bind to the newly discovered service in real time, potentially choosing a different Web Service for each interaction. Unfortunately, Web Services rarely if ever worked this way. Registries ended up doing little more than resolving endpoint references at run time, similar to the way DNS resolves domain names – in other words, they provided late binding. Such late binding adds some flexibility to an interaction, but typically at the expense of performance. Today, however, dynamic coupling and dynamic schemas enable any client to discover at run time all the metadata it requires to interact with any endpoint, without sacrificing performance – what I call extreme late binding.

Dynamic Constraint Satisfaction. The publication of Services at design time for later discovery shifted SOA’s focus from integration to governance. How are you going to manage all the Services in your directory – let alone actually reuse any of them – unless you are able to create and enforce policies across your organization for how to do so properly? Yes, SOA management tools (helpfully renamed API management tools for the 2010s) provide some measure of API governance, but typically constrained to the technical context of software interactions. However, ask a business stakeholder what governance means to them, and you’ll get an entirely different context for the word. While some policies are technical in nature and apply narrowly to specific APIs or applications, others are more business-centric and apply broadly across departments or even entire organizations. To enforce the full breadth of such policies properly, your run time environment must essentially solve for the combination of all applicable policies dynamically at run time across the entire application environment – a classic dynamic constraint satisfaction problem.

If you believe any of these patterns is nothing more than an old pattern warmed over with a new name, you may be missing something important. True, each of these patterns builds upon patterns that came before, but they all advance the discussion of Agile Architecture to a new level. On the other hand, if you think any of the above patterns are too difficult to implement – if it sounds like you need some kind of magic wand to make this vision work – then I’m here to tell you, I’ve seen a platform that can implement all four patterns, and furthermore, can do so without sacrificing performance. Thus we know they are possible. The question now is, why isn’t everyone doing them?

You may, however, believe that you’re actually implementing some or all of these patterns, either as an architect or as a vendor whose product supports such patterns for your customers. If so, I want to hear from you. Intellyx wants to tell your story.

The Intellyx Take

The Agile Architecture bar is set. Vendors should know what their products must do. Architects have some insight into the patterns they must follow. And business stakeholders can finally rest assured that at least it’s possible to achieve technology-enabled business agility. True, it’s difficult. Many of the pieces are only just now falling into place. Levels of maturity are low across the board. But we’re on our way.